Punch press

ABSTRACT

A punch press comprising (i) a tool set magazine that is located above a work table for supporting a workpiece and is juxtaposed with a main frame for supporting a punching head and (ii) a tool set delivery system for delivering tool sets between the tool set magazine and the punching head. A tool set mounting method comprising the steps of: (a) inserting the tool set delivery means into a tool set mounting section in a horizontal direction with a very small gap between the contact surface of an punch and its corresponding surface of the tool set mounting section opposite to the punch&#39;s contact surface and between the contact surface of a die and its corresponding surface of the tool set mounting section opposite to the die&#39;s contact surface; (b) lowering the tool set delivery means after the inserting step in such a direction that the small gap between the contact surface of the die and its corresponding surface of the tool set mounting section is eliminated; and (c) pulling the tool set delivery means out of the tool set mounting section in the horizontal direction after the lowering step while leaving the punch and die to be retained in the tool set mounting section.

TECHNICAL FIELD

The present invention relates to a punch press in which a large numberof tool sets (punch and die combination) can be stored to deal withvarious sorts of workpieces and which is capable of performing tool setreplacement at high speeds. The invention also relates to a tool setmounting method adapted in such a punch press, for mounting a punch anda die on the tool set mounting section of the punching head.

BACKGROUND ART

Conventionally, turret punch presses are generally used as a punchingmachine that is able to singly produce blanks of a plurality of certainshapes. A turret punch press comprises a pair of upper and lower turretswhich hold punches and dies respectively and punches a workpiece withthe punch and die which have been set in positions under a hammer byindexing. The turret punch presses can deal with a comparatively smallnumber of lots, say, 100 to 5,000 lots so that they have met so far theneeds of their market as a machine tool suited for use in the smallquantity production of multiple kinds of items.

In recent years, however, there have arisen strong demands in the markettowards the sales of multiple items in a much smaller number of lotswith short delivery times. Under such a situation, the conventionalturret punch presses, which can hold up to about 70 tool sets only, canno longer meet the market demands.

To overcome this problem, one turret punch press provided with anautomatic tool set replacement system has been proposed and put topractical use. According to this punching machine, a tool set storage(i.e., tool set repository) for storing a number of tool sets isincorporated in or installed separately from the turret punch press andthe automatic tool set replacement system supplies tool sets to thepunching head from the tool set storage.

Japanese Patent Publication No. 4-11283 (1992) discloses one example ofpunch presses provided with an automatic tool set replacement system.According to this publication, a magazine for storing tool sets isdisposed, in the form of an arc, in the area around the center ofrotation of a tool mounting/dismounting apparatus. Japanese PatentPublication Laid-Open No. 4-13424 (1992) discloses another example inwhich a tool set storage is disposed within a gate-like frame and a toolset replacement system is provided so as to reciprocate freely betweenthe tool set storage and the turret. A further example is disclosed inJapanese Patent Publication Laid-Open No. 61-115630 (1986) in which atool set magazine is so supported as to be rotatable about a horizontal,geometric axis and tool set replacement is performed by the linear,replacing motion of a tool set replacement system.

All of the prior punch presses with an automatic tool set replacementsystem disclosed in the above publications however fail in remarkablyincreasing the capacity of the tool set magazines to accommodate a largenumber of tool sets. In addition, the magazines of these punch pressesrequire an extremely large space for installation if a number of toolsets are accommodated in them, which increases the distance between thepunching head and the tool set storage position (i.e., the distance fortool set delivery), resulting in an increase in the time required fortool set replacement. As described above, in the prior turret punchpresses equipped with an automatic tool set replacement system, ifemphasis is placed on tool set replacement speed, it becomes difficultto increase the number of tool sets to be stored, and on the other hand,if emphasis is placed on the number of tool sets to be stored, tool setreplacement speed decreases.

In the case of a punch press with an automatic tool set replacementsystem, a so-called tool set replacement operation is necessary, inwhich a tool set with which punching operation has been done is removedfrom the punching head while another tool set to be used for the nextpunching operation is mounted on the punching head.

One conventional example of tool set replacement systems forautomatically performing such a tool set replacement operation isdisclosed in Japanese Patent Publication No. 54-6751 (1979). Accordingto the publication, a holder which is equipped with a holding mechanismfor holding a tool set is inserted, in a horizontal direction, into thetool set mounting section of the punching press and while the tool setis locked by a locking device within the tool set mounting section, theholding mechanism is disengaged from the holder so that only the holdercan be removed from the punch press in a horizontal direction. JapanesePatent Publication No. 4-13425 (1992) discloses another tool setreplacement system which is horizontally movable to mount or dismount atool set for replacement, and this tool set replacement system isequipped with a disengagement system for disengaging the system from theturret.

The tool set replacement system disclosed in the publication No. 54-6751suffers from the following problem. Since a tool set is inserted only bya reciprocating motion, the gap between the tool set and the ramreceiving section can be made small provided that the operator carefullyinserts the tool set and makes certain by touching the tool set.However, when automatic replacement is performed, a somewhat generousgap should be kept between them, which inevitably causes backlash aftermounting the tool set. Further, this system is designed to hold a toolset only by the resilient deformation of tool set holding arms andtherefore positioning of the holder cannot be performed at a high speed.The tool set replacement system disclosed in the publication No. 4-13425as mentioned above is also constructed so as to insert a tool set onlyby horizontal motion, so that an occurrence of backlash cannot beavoided. Another disadvantage of this system is that holders should beinstalled as many as tool sets.

In consideration of the foregoing problems, the invention aims toprovide a compact-sized punch press which can store a large number oftool sets to cope with the small quantity production of multiple kindsof items and which ensures a tool set replacement speed as high as thatof the conventional turret punch presses.

Another object of the invention is to provide a tool set mounting methodby which high-speed tool set replacement can be performed withoutpositioning the tool set delivery means with high accuracy and whichprevents the tool set from contacting the tool set mounting sectionduring insertion to eliminate the occurrence of an unpleasant soundcaused by the contact between the tool set and the tool set mountingsection.

DISCLOSURE OF THE INVENTION

The above objects can be achieved by a punch press according to a firstaspect of the invention, the punch press comprising a tool set magazinefor storing a number of tool sets and tool set delivery means fordelivering the tool sets between the tool set magazine and a punchinghead, wherein the tool set magazine is located above a work table forsupporting a workpiece and a support shaft of the tool set magazine liesin the longitudinal direction of the main frame for supporting apunching head.

In the punch press having the above construction, the tool set deliverymeans performs tool set delivery between the tool set magazine and thepunching head at a high speed so that the time required for tool setreplacement can be considerably reduced.

Preferably, the tool set magazine comprises a plurality of tool setholders arranged in lines along a horizontal support shaft, the lines ofthe tool set holders being arranged around the support shaft. In thiscase, each tool set holder is so supported as to be rotatable about thesupport shaft and holds a punch and a die assembled in a set. Such atool set magazine is capable of densely, compactly accommodating a largenumber of tool sets, which shortens the traveling distance of the toolset delivery means between the tool set magazine and the punching head.

It is preferable that the tool set magazine be vertically spaced aspecified distance apart from the position where the tool sets aremounted on or dismounted from the punching head such that the contour ofthe tool set magazine does not interfere with the workpiece beingprocessed by the punching head. Such arrangement makes it possible toinstall the tool set magazine in close proximity to the punching head soas not to interfere with a workpiece. This leads to an improvement inthe efficiency of tool set replacement.

The tool set delivery means is preferably disposed between the tool setmagazine and the main frame so as to be movable along the support shaftof the tool set magazine. This means is preferably designed to be liftedand lowered in a vertical direction.

Preferably, the tool set loading/unloading position where tool sets areloaded in or unloaded from the tool set magazine by means of the toolset delivery means is offset toward the punching head and located aboveor under the support shaft of the tool set magazine. This minimizes thelifting/lowering distance of the tool set delivery means at the time oftool set replacement, thereby to reduce the time required for tool setreplacement and provides constant conditions for loading or unloading oftool sets in relation to the tool set magazine, thereby to simplify themechanism.

In this case, the tool set loading/unloading position is preferably theposition where the axes of a tool set (i.e., a punch and a die) held bythe tool set holder stand upright, and the tool sets are loaded orunloaded in a direction that does not cross the support shaft of thetool set magazine but extends in a plane perpendicular to the supportshaft.

Further, the tool set delivery means preferably includes a hand thatperform mounting/dismounting of the tool sets in relation to thepunching head and loading/unloading of the tool sets in relation to thetool set magazine. As the hand for holding the tool set, two pairs ofgripping mechanisms each of which can grip a tool set, i.e., a punch anda die, may be used. These gripping mechanisms are preferably positionedat the respective lead ends of two arms that are so arranged as to havea substantially V-shape together in their plan view. Each grippingmechanism preferably comprises a plurality of pairs of gripping piecesfor gripping the punch and die assembled in a set. Further, eachgripping piece preferably has an engagement claw that is brought intoengagement with a V-shaped notch formed in each punch and die so thatthe punch and die are retained by the gripping piece.

Since the hand is composed of two gripping mechanisms integrally formed,the tool set to be used for the next punching operation can be mountedsequentially after removal of the tool set that has been used in theprior punching operation, by means of the rotation of the hand through asmall angle. With this arrangement, not only can the time required fortool set replacement be considerably reduced but also simplifiedconstruction can be adapted for the tool set mounting/dismountingoperation in relation to the punching head and for the tool setloading/unloading operation in relation to the tool set magazine.

Preferably, the tool set delivery means travels up to a projectingposition which is situated beyond one edge of the main frame, and at theprojecting position, the tool sets held by the tool set delivery meanscan be replaced. This facilitates the operation for loading a tool setfrom outside the punch press and the operation for replacing a worn-outtool set which has been used in the punching operation a specifiednumber of times with new one.

The projecting position may be also utilized as the discharging positionfor processed materials (i.e., products or debris remaining afterpunching-out). With this arrangement, the tool set delivery means can beused as a material discharging means to automate discharging ofmaterials from the work table.

According to a second aspect of the invention, there is provided a punchpress comprising:

(a) a tool set magazine having a number of tool set holders which arejuxtaposed in circumferential directions and axial directions of arotatably supported, horizontal support shaft and each of which can holda set of a punch and a die; and

(b) a tool set delivery means for loading the tool sets in and unloadingthem from the tool set holder having a desired address in the tool setmagazine, wherein each of the tool set holders has tool set receivingmembers arranged at multiple levels to receive the tool sets and each ofthe tool set receiving members has a tool set receiving section notchedtherein in which a specified portion of each tool set can be received bymoving the tool sets straight ahead or laterally.

In the invention having the above-described feature, the support shaftis rotated through a specified angle and the tool set delivery means ispositioned in relation to a tool set holder having a specified address,whereby the punch and die held by the tool set holder in an assembledcondition can be easily taken out. The tool sets are moved straightahead and laterally at the same level to be received and held by thetool set holder. This simplifies the tool set loading/unloadingoperation. In this case, if the tool set magazine is installed in closeproximity to the punching head thereby to reduce the travel distance ofthe tool set delivery means between the pressing head and the toolmagazine, which markedly reduces the time required for tool setreplacement. In the tool set magazine of the invention, tool set holdersare juxtaposed in circumferential directions and axial directions of thehorizontal support shaft, so that heavy-weight tool sets can be storedand arranged closely to one another in long lines parallel to thesupport shaft of the tool set magazine. This restricts the rotaryinertia force of the tool set holders, which occurs when they rotateabout the support shaft.

Preferably, the support shaft is a hollow shaft with a polygonalcross-section and tool set holding units each having a plurality of toolset holders are attached to the external surface of the support shaft.This makes the support shaft light-weight, without decreasing themechanical strength of the support shaft and allows easyinstallation/removal of the tool set holding units.

Each of the tool set holding units includes a base attached to theexternal surface of the support shaft; a plurality of support bracketseach of which projects from the base at a specified angle with respectto the circumferential direction of the support shaft; and a pluralityof tool set holders each of which is attached to the lead end of eachsupport bracket and which are juxtaposed at specified intervals. Thisarrangement leads to improvements in the workability and maintainabilityof the tool set holding units.

Preferably, each of the tool set holders includes tool set receivingmembers which are aligned at multiple levels to receive the tool sets.Each tool set receiving member has a tool set receiving section notchedtherein and the tool sets move straight ahead and laterally so that aspecified portion of each punch and die is received in the correspondingtool set receiving section. Accordingly, the straight-ahead movement andlateral movement of the tool sets at the same level allow the tool setsto be received and held by the tool set holder, which facilitatesloading and unloading of the tool sets.

Each tool set receiving member may include engagement means for engagingthe tool set inserted in its tool set receiving section. In this case,the engagement means is preferably a leaf spring that is attached to theupper surface or lower surface of the tool set receiving member so as tobe brought into engagement with the engagement recess of the punch anddie. The provision of such engagement means enables it to stably holdthe tool sets accommodated in the tool set holder even if the tool setholder changes in position due to the rotation of the tool set magazine.

At both sides of the tool set receiving section of the lowest tool setreceiving member, fixed dogs may be provided for releasing the tool setholding force of the tool set delivery means. This arrangement enablesit to automatically release the tool set holding force of the tool setdelivery means simply by making the tool set delivery means close to thetool set holder when the tool sets are loaded in or unloaded from thetool set magazine, so that loading and unloading of the tool set can beautomatically performed.

According to the invention, there is provided a tool set mounting methodfor mounting a punch and a die on the tool set mounting section of apunching head, said punch and die being assembled in a set and held bytool set delivery means, the method comprising the steps of:

(a) inserting the tool set delivery means into the tool set mountingsection in a horizontal direction with a very small gap between thecontact surface of the punch and the corresponding surface of the toolset mounting section opposite to the punch's contact surface and betweenthe contact surface of the die and the corresponding surface of the toolset mounting section opposite to the die's contact surface;

(b) lowering the tool set delivery means after the inserting step insuch a direction that the small gap between the contact surface of thedie and the corresponding surface of the tool set mounting sectionopposite to the die's contact surface is eliminated; and

(c) pulling the tool set delivery means out of the tool set mountingsection in the horizontal direction after the lowering step whileleaving the punch and die to be retained in the tool set mountingsection.

According to the above method, for mounting a tool set on the tool setmounting section, a set of a punch and a die held by the tool setdelivery means is inserted into the tool set mounting section while avery small gap is maintained between the contact surface of the punchand its associated surface in the tool set mounting section and thecontact surface of the die and its associated surface in the tool setmounting section. Then, the tool set delivery means is lowered in such adirection as to eliminate the small gap between the contact surface ofthe die and its associated surface in the tool set mounting section.After the lowering step, the punch and die are held in the tool setmounting section and the tool set delivery means which has released thetool set (punch and die) from the held condition is finally pulled outin the horizontal direction to complete the tool set mounting operation.

This method not only reduces the contact sound made when the tool setsare inserted but also makes it possible to perform tool set replacementat a high speed without accurately positioning the tool set deliverymeans. In addition, since the level of the upper surface of the die,that is, the pass line for workpieces can be maintained constantimmediately after the insertion of the tool set, damage to a workpiececan be prevented when the workpiece is laid over the die during tool setdelivery.

The contact surface of the punch and its associated surface in the toolset mounting section are brought into close contact with each other byprocessing the workpiece with the punch.

This contact with each other may be achieved by holding the punch in thetool set mounting section. In this case, the part of the punch to bepressed when the punch is held may be tapered so that the contactsurface of the punch and its associated surface in the tool set mountingsection can be brought into close contact with each other.

The punch may be held in the tool set mounting section after the closecontact between the contact surface of the punch and its associatedsurface of the tool set mounting section has been accomplished bylowering a ram disposed in the tool set mounting section by a specifiedamount.

Other objects of the present invention will become apparent from thedetailed description given hereinafter. However, it should be understoodthat the detailed description and specific example, while indicating apreferred embodiment of the invention, are given by way of illustrationonly, since various changes and modifications within the spirit andscope of the invention will become apparent to those skilled in the artfrom this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1 to 28 provide illustrations of a punch press and tool setmounting method according to one embodiment of the invention.

FIG. 1 is a plan view of the punch press according to the embodiment ofthe invention.

FIG. 2 is a view taken on line A--A of FIG. 1.

FIG. 3 is a right side view of the punch press shown in FIG. 2.

FIG. 4 is a partially cut-away sectional view of a tool set magazine.

FIG. 5 is a view illustrating a tool set holding unit in the tool setmagazine when viewed in the direction of arrows B of FIG. 4, in the viewof which some tool set holders are omitted.

FIG. 6 is a sectional view showing, in enlarged form, an essential partof the tool set holding unit of the tool set magazine.

FIG. 7(a) is a longitudinal sectional view of a punch.

FIG. 7(b) is a plan view of the punch.

FIG. 8(a) is a plan view of a die.

FIG. 8(b) is a longitudinal sectional view of the die.

FIG. 9(a) is a side view of the tool set holder.

FIG. 9(b) is a sectional view of the tool set holder taken on line C--Cof FIG. 9(a).

FIG. 10(a) is a plan view showing an essential part of a first tool setreceiving member in the tool set holder.

FIG. 10(b) is a sectional view of the first tool set receiving membertaken on line D--D of FIG. 10(a).

FIG. 11 is a plan view showing an essential part of a second tool setreceiving member in the tool set holder.

FIG. 12 is a plan view showing an essential part of a third tool setreceiving member in the tool set holder.

FIG. 13 is a plan view showing an essential part of a forth tool setreceiving member in the tool set holder.

FIG. 14 is a plan view showing an essential part of a fifth tool setreceiving member in the tool set holder.

FIG. 15 is a plan view of a hand.

FIG. 16 is a partial sectional view of the hand taken on line E--E ofFIG. 15.

FIG. 17(a) is an enlarged view showing an essential part of a grippingpiece of the hand, for gripping the punch.

FIG. 17(b) is an enlarged view showing an essential part of a grippingpiece of the hand, for gripping a stripper.

FIG. 17(c) is an enlarged view showing an essential part of a grippingpiece of the hand, for gripping the die.

FIG. 18 is an enlarged partial sectional view showing a lock mechanismof the gripping pieces of the hand.

FIG. 19 is an explanatory view illustrating a tool set mountingoperation.

FIG. 20 is a view taken along the direction of arrow F of FIG. 19.

FIG. 21(a) is a plan view of a tool set mounting section of a punchinghead.

FIG. 21(b) is a view taken along the direction of arrow G of FIG. 21(a).

FIG. 22 shows one example of the way of holding tool sets by the toolset holder.

FIG. 23 corresponds to FIG. 22 and shows the way of tool set holding bythe first tool set receiving member of the tool set holder.

FIG. 24 corresponds to FIG. 22 and shows the way of tool set holding bythe second tool set receiving member of the tool set holder.

FIG. 25 corresponds to FIG. 22 and shows the way of tool set holding bythe third tool set receiving member of the tool set holder.

FIG. 26 corresponds to FIG. 22 and shows the way of tool set holding bythe forth tool set receiving member of the tool set holder.

FIG. 27 corresponds to FIG. 22 and shows the way of tool set holding bythe fifth tool set receiving member of the tool set holder.

FIG. 28 is a front view of a mechanism for discharging used materials.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings, a punch press and a tool set mountingmethod will be described according to a preferred embodiment of theinvention.

FIGS. 1 to 3 show the whole construction of a punch press according toone embodiment of the invention. In this punch press, a main frame 1 ofa portal structure stands upright on a fixed bed 2 and a movable table 3which is movable in the direction of the Y-axis (see FIG. 1) is disposedtransversely to and under the main frame 1. The main frame 1 is providedwith a work center 4 which is disposed at a position somewhat offsetfrom the middle position of the main frame 1 in a longitudinal direction(to the right in FIGS. 1 and 2), with its vertical axis determined. Inthe work center 4, there is provided a ram (not shown) which is drivendownwardly for operation and has, at the lower end thereof, a punchinghead 4a on which a punch is to be mounted. A mount table 4b on which adie is to be mounted is provided on the fixed bed 2 so as to face thepunching head 4a. One side of the movable table 3 is provided with acarriage 5 that includes a work clamp 5a for holding a workpiece. Thecarriage 5 is movable on the movable table 3 in the direction of theX-axis (see FIG. 1). In the punch press having the above-describedconstruction, a workpiece to be punched is held by the work clamp 5a andthe position of the workpiece in the direction of the Y-axis isdetermined by the movement of the movable table 3 relative to the workcenter 4, while its position in the direction of the X-axis on themovable table 3 is determined by the movement of the carriage 5.

At a position a predetermined distance spaced from the main frame 1, aprismatic tubular (or cylindrical), tool set magazine 6 is disposed withits axis parallel to the main frame 1. Provided between the tool setmagazine 6 and the main frame 1 is a tool set delivery system 7. Thetool set delivery system 7 comprises (i) a rail 8 running in parallelwith the tool set magazine 6 and with the main frame 1; (ii) an ATC(Automatic Tool Changer) carriage 9 movable along the rail 8; (iii) alifting shaft frame 10 that can be lifted and lowered in relation to theATC carriage 9; (iv) a traveling shaft frame 11 horizontally disposed atthe lower end of the lifting shaft frame 10; (v) a carrier 12 (see FIG.4) movable along the traveling shaft frame 11; and (vi) a hand 13 thatis horizontally turnable through a specified angle in relation to thecarrier 12. Reference numeral 14 designates a supporting means for anenergy supply cable which supplies energy to the driving mechanism ofthe tool set delivery system 7.

The tool set magazine 6 is made in a laterally elongated form andcomprises (i) a support shaft 15 disposed at the center of the tool setmagazine 6; and (ii) a number of tool set holding units 16 (see FIG. 4)that are fixedly attached to the support shaft 15, being aligned on thecircumference of the support shaft 15 and in the axial direction of theshaft 15. The support shaft 15 is rotatably supported at both endsthereof by means of bearings 18 to the upper parts of magazine supportframes 17 which are formed separately from the main frame 1. A magazineindexing and actuating means 19 indexes the support shaft 15 to obtainrotation angles and rotates the support shaft 15 through the rotationangles.

The tool set magazine 6 is covered except for the area that extends inthe axial direction of the tool set magazine 6 along a part of the rail8 where loading/unloading of tool sets is performed by the hand 13. Thetool set magazine 6 is vertically spaced a specified distance from theposition where tool sets are mounted on or dismounted from the punchinghead 4a so that the periphery of the tool set magazine 6 does notinterfere with the movement of a workpiece to be processed by thepunching head 4a.

As shown in FIGS. 4 and 6, the support shaft 15 is hollow except itsboth ends and has a rectangular shape in cross-section. The supportshaft 15 is provided with attaching parts 15a along its entire lengthoutwardly and a number of tool set holding units 16 are removablyattached to these attaching parts 15a. Each tool set holding unit 16 iscomposed of (i) a support body 22 comprising a rectangular base 20 andsupport brackets 21 which are forked from the base 20, projectingtherefrom; and (ii) a plurality of tool set holders 23 (three holders inthis embodiment) which are respectively supported at the respective leadends of the support brackets 21. These tool set holders 23 are alignedat equal intervals in the circumferential direction of the support shaft15. The base 20 is secured to a certain position of the support shaft 15by positioning with a positioning pin 24 and by tightening with bolts25, with an irregular portion 20a formed at the back of the base 20being engaged with a groove 15b formed in the attaching part 15a of thesupport shaft 15. Each tool set holder 23 is attached to a bearing seat26 which has a certain width and extends over the entire length of thelead end of the support bracket 21. This bearing seat 26 has a bearingsurface 26a arranged at a specified angle. The projecting length of eachsupport bracket 21 from the base 20 is so determined that all the toolset holders 23 take the same posture after being mounted in relation tothe axis of the rotation of the support shaft 15.

Reference is made to FIGS. 7 and 8 to describe a tool set 27 used in thepunch press of the embodiment.

As shown in these figures, the tool set 27 is composed of (i) a punch28; (ii) a stripper 29 incorporated in the punch 28; and (iii) a die 30.These three members grouped in a set are held by the tool set holdingsections of the tool set holder 23.

The punch 28 has (i) a punch tip 31 of a desired shape and (ii) a clampshank 32 having a certain dimension and shape in which the periphery isbrought into holding engagement with the punching head 4a when the punch28 is mounted on the head 4a. These members 31 and 32 are integrallycoupled to each other with the help of a bolt 33. A retaining ring 34for use in delivery is fixedly fitted on the base part of the clampshank 32. An engagement groove 32a with a V-shaped cross-section runsthroughout the periphery of the clamp shank 32. A retaining groove 34awith a V-shaped cross-section runs throughout the periphery of theretaining ring 34. At opposed positions, the retaining ring 34 is cuttoward its axis in an opposite relation with each other to make a pairof V-shaped notches 34b on the plane which passes the axis of theretaining ring 34. On the upper surface of the retaining ring 34, apositioning pin 34c is provided at a position that is 90° shifted fromthe positions of the pair of V-shaped notches 34b and that is spacedfrom the center of the retaining ring 34 at a specified distance. Thispositioning pin 34c projects from the upper surface of the retainingring 34 in parallel with the axis of the retaining ring 34. Countersunkengagement recesses 34d are also provided at suitable positions of theupper surface of the retaining ring 34 to prevent the punch 28 fromshifting when it is accommodated in the tool set holding section. Itshould be noted that the external shape and attaching position of thepositioning pin 34c as well as the shape and positions of the engagementrecesses 34d are preferably standardized irrespective of the shape ofthe punch 28.

Generally, the stripper 29 is made from a material softer than thematerial of the punch 28. The stripper 29 is fitted on the peripherypart of the punch 28 from the bottom such that the stripper 29 issupported to be vertically slidable. The stripper 29 also has, at itsperiphery, a V-shaped retaining groove 29a and a pair of V-shapednotches 29b (see FIG. 25) identical with the V-shaped notches 34b of thepunch 28. The stripper 29 may have any shape and any structure accordingto the configuration of the punch 28. For example, the stripper 29 doesnot need to slide vertically but has a cushioning property, depending onthe configuration of the punch 28. In cases where the stripper 29 isincorporated in a punch 28 having a small diameter, the V-shapedretaining groove 29a and the V-shaped notches 29b may be eliminated.

The die 30 includes, at its periphery, a V-shaped retaining groove 30aused for holding and a pair of V-shaped notches 30b similar to those ofthe punch 28. At the position on the periphery shifted from thepositions of the V-shaped notches 30b by 90°, a notch 30c used forpositioning is formed. At the underside of the die 30, there is providedat least one engagement groove 30d that runs in parallel with theV-shaped notches 30b. The die 30 has, at an appropriate position on theupper surface thereof, an engagement recess 30e formed identically withthe engagement recess 34d of the punch 28.

Next, the detailed construction of the tool set holders 23 for holdingthe tool set 27 will be described with reference to FIGS. 4 to 6 andFIGS. 9 to 14.

In each tool set holder 23, five tool set receiving members 35, 36, 37,38, 39 are tightened and secured by means of a bolt 41 such that thesetool set receiving members are spaced in parallel relationship with fourspacers 40 interposed at their base ends so that the gaps between themcorrespond to the widths of the punch 28, stripper 29 and die 30,respectively. As shown in FIG. 5, each tool set holder 23 has five toolset holding sections for receiving and holding each member of the toolset 27, these sections being spaced at a predetermined pitch P. Itshould be noted that, according to this embodiment, three tool setholders 23 are aligned in a row in the circumferential direction of thesupport shaft 15 and five rows of tool set holders 23 are arranged inthe axial direction of the support shaft 15, so that fifteen tool setholders 23 are included in each tool set holding unit 16, and that fourtool set holding units 16 are disposed in a row around the support shaft15, and five such rows are arranged in the axial direction of thesupport shaft 15, so that twenty tool set holding units 16 are providedin total. Accordingly, three hundred tool set holders 23 (i.e.,15×20=300) are provided in total in the tool set magazine 6. In otherwords, three hundred tool sets 27 each composed of the punch 28,stripper 29 and die 30 can be stored within the tool set magazine 6.

In each tool set holding section of the tool set holder 23, the punch 28is held by the first tool set receiving member 35 and the second toolset receiving member 36. Therefore, the first tool set receiving member35 is cut, from an open end side to a base end side 35a, to form a toolset receiving section 35A as shown in FIG. 10, the tool set receivingsection 35A having such a width that the clamp shank 32 of the punch 28can penetrate. In the section 35A, laterally oriented notches 35b, 35care formed so as to correspond to the clamp shank 32 and positioning pin34c of the punch 28. After the clamp shank 32 of the punch 28 has beenreceived by the tool set receiving section 35A, the punch 28 is movedlaterally in the axial direction of the support shaft 15 at a specifiedposition, thereby bringing the clamp shank 32 and the positioning pin34c into holding engagement with the notches 35b, 35c respectively.Apart from the tool set receiving section 35A, the tool set receivingmember 35 has an engagement leaf spring 42 secured thereto with a boltand this leaf spring 42 has a projection 42a which comes into engagementwith the engagement recess 34d formed on the upper surface of the punch28 thereby preventing the punch 28 from shifting laterally. At theattached position of the engagement leaf spring 42, a hole 35B is formedon the upper side of the engagement leaf spring 42. Note that chain linea of FIG. 10(a) indicates the center line of insertion of the punch 28(tool set 27) (hereinafter referred to as "insertion center line a"),while chain line b indicates the center line of the lateral movement ofthe punch 28 (tool set 27) (hereinafter referred to as "lateral movementcenter line b") (The tool set receiving members 36, 37, 38, 39 also havesimilar center lines).

The second tool set receiving member 36 is cut in the same direction asthe tool set receiving section 35A of the first tool set receivingmember 35 to form a tool set receiving section 36A, as shown in FIG. 11.Projecting from the underside of the second tool set receiving member 36are two stopper pins 36a. These stopper pins 36a come into engagementwith a groove (not shown) formed on the top surface of the stripper 29to prevent the it from falling.

The third tool set receiving member 37 has, as shown in FIG. 12, anengagement leaf spring 43 with a projection 43a which has the samestructure as that of the engagement leaf spring 42. This leaf spring 43lies at a position somewhat distant from the lateral movement centerline b in parallel with the center line b. The tool set receiving member37 has a hole 37B formed at a lower position of the movable part of theengagement leaf spring 43. Reference numeral 37C designates anotherhole.

The forth tool set receiving member 38 is cut in the same direction asthe tool set receiving sections 35A, 36A of the first and second toolset receiving members 35, 36 to form a tool set receiving section 38A,as shown in FIG. 13. Formed at the innermost part of the tool setreceiving section 38A is a notch 38B which is formed in parallel withthe lateral movement center line b. At the underside of the tool setreceiving member 38, an engagement leaf spring 44 identical with theengagement leaf springs 42, 43 is disposed under the notch 38B and itsmovable part is directed toward the notch 38B. A projection 44a attachedto the movable part of the leaf spring 44 comes into engagement with theengagement recess 30e formed on the top surface of the die 30, therebypreventing a fall of the die 30.

The fifth tool set receiving member 39 is cut in the same direction asthe first, second and forth tool set receiving members 35, 36, 38 toform a rectangular tool set receiving section 39A, as shown in FIG. 14.The tool set receiving section 39A is designed to receive a projectionattached to other tools (e.g., a tup unit) than the die 30. Formed onthe top surface of the tool set receiving section 39 as to projecttherefrom are stopper pins 39a that come into engagement with apositioning groove 30d formed in the die 30 to prevent a fall of the die30. A pair of fixed dogs 45 are disposed at both sides of the tool setreceiving section 39A across its width. These dogs 45 project forwardsin parallel with the insertion center line a. The top surfaces of thefixed dogs 45 are at the same level as the top surface of the tool setreceiving member 39 and are inclined at the lead ends thereof to forminclined faces 45a.

The tool set holder 23 having the above-described construction isfabricated such that the insertion center lines a of the tool setholding sections in all the tool set receiving members 35, 36, 37, 38,39 exist in the same vertical plane and such that the members of thetool set 27 are inserted and held in the predetermined assigned spacesformed between the tool set receiving members 35, 36, 37, 38 and 39. Asclear from FIG. 4, the tool set holders 23 rotate about the axis of thesupport shaft 15 in such a manner that the axis of the tool set 27inserted in the tool set holding sections makes a right angle with theaxis of the support shaft 15 and such that the axis of the tool set 27becomes vertical when each tool set holder 23 is at the deliveryposition (i.e., tool set loading/unloading position) S where the toolset 27 is delivered by the hand 13 of the ATC carriage 9. It should benoted that the delivery position S is located under the axis of thesupport shaft 15, being offset to the punching head 4a.

The loading and unloading direction of the tool set 27 at the deliveryposition S exists in a plane perpendicular to the support shaft 15 andperpendicular to the axis of the tool set 27.

In the above arrangement, the magazine indexing and actuating means 19indexes the support shaft 15 of the tool set magazine 6 to obtain arotation angle and rotates the support shaft 15 through the rotationangle, while the ATC carriage 9 of the tool set delivery system 7 movesalong the rail 8 toward a specified position to place the carrier 12 andhand 13 at specified positions, so that a desired tool set 27 can beloaded or unloaded.

FIGS. 15 and 16 show the hand 13 of the tool set delivery system 7.

As mentioned above, the hand 13 can horizontally turn through aspecified angle relative to the carrier 12 (see FIG. 4) and can belifted and lowered between the level at which the tool set 27 is loadedin unloaded from the tool set magazine 6 and the level at which the toolset 27 is mounted on or dismounted from the punching head 4a and mounttable 4b of the work center 4. The hand 13 comprises two arms 46 whichproject from a base part (this part is the center of rotation) such thatthese two arms 46 together take a V-shape in their plan view. The leadend of each arm 46 has a gripping mechanism 47 for retaining the toolset 27 in an assembled condition. The angle between the two arms 46 isan acute angle, and more preferably about 70°.

In each of the gripping mechanisms 47, an upper bracket 48 and a lowerbracket 49 are fixedly attached to a mounting seat 46' located at thelead end of the arm 46. Attached to the upper bracket 48 are a pair ofgripping pierces 50 for the punch 28 and a pair of gripping pieces 51for the stripper 29. Attached to the lower bracket 49 is a pair ofgripping pieces 52 for the die 30. These gripping piece pairs 50, 51, 52are respectively symmetrically disposed and their base parts arepivotally supported to the brackets 48 or 49 with the help of pins 53,54. Coil springs 55 inserted in the trail ends of the gripping piecepairs 50, 51, 52 are energized to allow engagement claw pairs 50a, 51a,52a provided at the leads ends of the gripping piece pairs 50, 51, 52 tocome into engagement with the V-shaped notches 34b of the retaining ring34 of the punch 28, the V-shaped notches 29b formed on the periphery ofthe stripper 29, and the V-shaped notches 30b formed on the periphery ofthe die 30, respectively. The engagement claws 50a, 51a, 52a arerespectively made in the form of a pin parallel with the axis of holding(i.e., the axis of the tool set 27) so that they can engage with theV-shaped notches 34b of the retaining ring 34 of the punch 28, theV-shaped notches 29b of the stripper 29, and the V-shaped notches 30b ofthe die 30, respectively (see FIG. 17).

The lead ends of the gripping piece pairs 50, 51, 52 are tapered downwith chamfered upper and lower surfaces so as to be fitted in theV-shaped retaining groove 34a of the retaining ring 34 of the punch 28,the retaining groove 29a of the stripper 29 and the retaining groove 30aof the die 30, respectively. The lateral movements of the gripping piecepairs 50, 51, 52 are restricted by lock pins 56 each of which is locatedsomewhat distantly from the center of pivot in the respective main partof the gripping pieces 50, 51, 52. When the lock pins 56 are released,the lead ends of the gripping piece pairs 50, 51, 52 where theengagement claws 50a, 51a, 52a are attached move against the energizingforces of the coil springs 55 to open.

As shown in FIG. 18, each of the lock pins 56 is arranged so as to beslidable in a vertical direction, penetrating vertically running,lock-pin penetration holes 57, 58 which are formed in a wing 48a of theupper bracket 48 and a wing 49a of the lower bracket 49, respectively.The lock pin 56 includes small diameter parts 56a and large diameterparts 56b, these parts having specified lengths and being positioned inrelation to the gripping pieces 50, 51, 52 in the lock-pin penetrationholes 57, 58. The lock pin 56 is energized downwards (i.e., lockingdirection) all the time by means of a coil spring 59 inserted betweenthe upper and lower wings 48a and 49a. The lower end 56c of the lock pin56 protrudes downward from the underside of the lower bracket 49.

When a brim 56d projecting from the lock pin 56 comes in abutment withthe top surface of the wing 49a of the lower bracket 49 owing to theenergizing force of the coil spring 59, the large diameter parts 56bcome to the positions (indicated by solid lines in FIG. 18) in thelock-pin penetration holes 57, 58, these positions corresponding to thegripping pieces 50, 51, 52, so that the gripping pieces 50, 51, 52 arelocked. For unlocking, the lower end 56c of the lock pin 56 in the abovelocking condition is pushed upward by the fixed dogs 45 provided at thelowest tool set receiving member 39 of the tool set holder 23 or byfixed dogs 67 (described later) provided at the work center 4. The lockpin 56 thus moves up against the energizing force of the coil spring 59and slides such that the small diameter parts 56a moves to the positions(indicated by chain lines in FIG. 18) in the lock-pin penetration holes57, 58, the positions corresponding to the gripping pieces 50, 51, 52.As a result, the gripping pieces 50, 51, 52 are released from theirlocked condition. Note that reference numeral 60 in FIGS. 15 and 16designates a lock sensor that senses the locking condition or unlockingcondition of the lock pins 56 thereby checking the held condition of thetool set 27.

As shown in FIG. 19, the punching head 4a on which the punch 28,stripper 29 and die 30 retained by the hand 13 are to be mounted has (i)an engaging member 61 having a projection 61a to be engaged with theV-shaped engagement groove 32a of the clamp shank 32; (ii) a punch clampclaw 62 that is lowered by the operation of a punch clamp cylinder (notshown) to hold the clamp shank 32 in cooperation with the engagingmember 61; and (iii) an engaging member 63 having a projection 63a to beengaged with the V-shaped retaining groove 29a of the stripper 29. Thepunching head 4a also has, as shown in FIG. 20, two stripper clampcylinders 64 and two stripper clamp claws 65 which are operationallycoupled to the stripper clamp cylinders 64, respectively. These stripperclamp claws 65 retain the peripheral of the stripper 29 at twopositions. Similarly, the mount table 4b provided on the fixed bed 2, onwhich the die 30 is to be mounted, has die clamp cylinders and die clampclaws (both are not shown) which are constructed similarly to thestripper clamp cylinders 64 and the stripper clamp claws 65. With thesedie clamp cylinders and die clamp claws, the die 30 is positioned at aspecified position.

Referring to FIG. 21, the mount table 4b is provided with an unlockingmeans 66 for releasing the locking force of the lock pins 56 of the hand13. The unlocking means 66 operates the fixed dogs 67 incorporated inthe mount table 4b such that the fixed dogs 67 push up the lock pins 56in the same manner as the fixed dogs 45 of the tool set holder 23 torelease the gripping pieces 50, 51, 52 from their locked condition.

Now there will be explained the operation for delivering the tool set 27between the tool set magazine 6 and the work center 4 by means of thetool set delivery system 7 of the above-described structure.

As shown in FIG. 22, the punch 28, stripper 29 and die 30 are held bythe tool set receiving members 35, 36, 37, 38, 39 and accommodated inthe assembled condition in the tool set holding sections of the tool setholder 23.

When the tool set 27 is accommodated in the tool set holder 23, thepunch 28 is supported by the first tool set receiving member 35 and thesecond tool set receiving member 36 as indicated by chain line H₁ ofFIGS. 23 and 24. In this condition, the clamp shank 32, the positioningpin 34c and the projection 42a of the engagement leaf spring 42 engagewith the notches 35b, 35c and the recess 34d of the retaining ring 34,respectively.

The stripper 29 is supported by the second tool set receiving member 36and the third tool set receiving member 37 as indicated by chain line H₂of FIGS. 24 and 25. In this condition, the stopper pins 36a engage withthe groove formed on the top surface of the stripper 29 while theprojection 43a of the engagement leaf spring 43 engages with a recess(not shown) formed in the stripper 29.

The die 30 is supported in the condition indicated by chain line H₃ ofFIGS. 26 and 27 by means of the forth and fifth tool set receivingmembers 38, 39. In this condition, the stopper pins 39a engage with thepositioning grooves 30d of the die 30 while the projection 44a of theengagement leaf spring 44 engages with the recess 30e of the die 30.

Thus, even when the tool set magazine 6 is rotated about the supportshaft 15 to take out the tool set 27 therefrom, the tool set 27 will besecurely held, without falling down from the tool set holding sectionsof the tool set holder 23.

For tool set replacement, the movable table 3 is retracted in thedirection of the Y-axis to a predetermined position so that the hand 13can perform a horizontal turn. This retraction is carried out for fearof the interference by the hand 13. Specifically, since the tool setreplacement is performed on the assembled condition grouped in a set andthe die 30 is mounted on the mount table 4b that is lower than the passline for the workpiece, the hand 13 would interfere with the movabletable 3 or the workpiece when the hand 13 is lowered to the tool setdelivery position on the side of the work center 4.

After the address number of a desired tool set 27 has been selectedaccording to the program for operating the control mechanism, a commandis sent to the magazine indexing and actuating means 19 to rotate thesupport shaft 15 through a specified angle so that the desired tool set27 comes to the tool set delivery position (i.e., tool setloading/unloading position) S shown in FIG. 4. After the desired toolset 27 has reached the position S, the rotation of the support shaft 15is stopped.

While the tool set magazine 6 is indexed and rotated as mentioned above,the control unit releases a movement command to the tool set deliverysystem 7 from the control mechanism so that the ATC carriage 9 is movedalong the rail 8 to the position corresponding to the address of thedesired tool set 27 in the tool set magazine 6 and the carrier 12 islifted or lowered. Meanwhile, the hand 13 turns, moving either of itsgripping mechanisms 47 to the position opposite to the tool set deliveryposition S.

Thereafter, the gripping mechanism 47 moves forward to the tool setholder 23 to put the gripping pieces 50, 51, 52 for the punch 28,stripper 29 and die 30 in the tool set holding sections. The lower ends56c of the lock pins 56 of the gripping mechanism 47 in the hand 13 arebrought into contact with the top surfaces of the fixed dogs 45 of thetool set receiving member 39 in the tool set holder 23, whereby the lockpins 56 are pushed up against the energizing forces of the coil springs59. This allows the respective small diameter parts 56a formed in themiddle parts of the lock pins 56 to be placed at the positions in thelock-pin penetration holes 57, 58 of the gripping pieces 50, 51, 52, thepositions corresponding to the gripping pieces 50, 51, 52. As a result,the gripping pieces 50, 51, 52 become free within the respective gapsbetween the small diameter parts 56a of the lock pins 56 and thelock-pin penetration holes 57, 58, so that the engagement claws 50a,51a, 52a formed at the lead ends of the gripping pieces 50, 51, 52become laterally movable into the V-shaped retaining grooves 34a, 29a,30a to hold the punch 28, stripper 29 and die 30, respectively.

After the hand 13 has reached the foremost position, regarding the punch28, the engagement claws 50a of the gripping pieces 50 engage with theV-shaped notches 34b of the retaining ring 34 as shown in FIG. 23.Similarly, regarding the stripper 29, the engagement claws 51a of thegripping pieces 51 engage with the V-shaped notches 29b as shown in FIG.25. Regarding the die 30, the engagement claws 52a of the grippingpieces 52 engage with the V-shaped notches 30b formed on the peripheryof the die 30 as shown in FIG. 27. In this condition, the grippingpieces 50, 51, 52 are once moved laterally in the axial direction (i.e.,the direction indicated by arrow T of FIG. 23) of the support shaft 15by a specified amount and retracted after releasing the engagementbetween the positioning pins and the notches. This allows the lock pins56 to be separated from the top surfaces of the fixed dogs 45, therebypulling back the gripping pieces 50, 51, 52 immediately by theenergizing forces of the coil springs 55 so that the gripping pieces 50,51, 52 are locked while holding the tool set 27. Thus, the tool set 27which has been taken from the tool set magazine 6 by the hand 13 becomesmovable in a securely held condition.

Once the tool set 27 thus held by the hand 13 has been retracted fromthe tool set delivery position S to the traveling position, it islowered to a predetermined level and then moved along the rail 8 to aposition near the work center 4. At the position near the work center 4,the hand 13 turns through a specified angle in a horizontal directionsuch that the arm 46 (i.e., dismounting hand) which holds no tool set ispositioned opposite to the punching head 4a. The hand 13 then stands byin this condition.

Upon completion of the punching operation by the use of the tool set 27held at the work center 4, the hand 13 is slightly lowered from thestand-by position. After that, the hand 13 moves in a horizontaldirection to allow the lead end of its dismounting hand to be directedforwards and inserted between the punching head 4a and the mount table4b. Prior to the tool set replacement by the hand 13, in the work center4, a die cover 68 (see FIG. 21) disposed so as to enclose the die 30mounted on the mount table 4b is lifted by the amount corresponding tothe thickness of the die 30 so that the die 30 can be exposed. The diecover 68 has, at a specified position, notches 68a which are formed inorder to avoid the interference with the lock pins 56 of the hand 13.The hand 13 is accordingly inserted into the work center 4, of whichinserting movement is followed by the pushing-up of the lock pins 56 bythe fixed dogs 67. This moves the engagement claws 50a, 51, 52a into thecontact with the V-shaped notches 34b of the retaining ring 34, theV-shaped notches 29b of the stripper 29 and the V-shaped notches 30b ofthe die 30 respectively, and by the virtue of the energizing forces ofthe coil springs 55, the tool set 27 is securely held by the engagementclaws 50a, 51a and 52a. Then, the retracting movement of the hand 13causes the tool set 27 to be pulled out of the work center 4, and thelock pins 56 are separated from the fixed dogs 67 when the moving speedof the hand 13 increases. This allows the large diameter parts 56b ofthe lock pins 56 in the lock-pin penetration holes 57, 58 to be placedat the positions corresponding to the gripping pieces 50, 51, 52,thereby locking the movement of the gripping pieces 50, 51, 52. Inconsequence, even if a shock occurs during acceleration or decelerationof the hand 13, the tool set 27 will not drop off the hand 13.

After the tool set 27 has been accordingly dismounted from the workcenter 4, the hand 13 turns about the base end through approximately 70°in a horizontal plane so that the arm 46 (i.e., mounting hand) whichholds a new tool set 27 to be mounted is placed in a position oppositeto the punching head 4a and sequentially moved horizontally to beinserted into the punching head 4a. After the hand 13 has been insertedbetween the punching head 4a and the mount table 4b, the lower ends 56cof the lock pins 56 are pushed up by the fixed dogs 67 to bring theengagement claws 50a, 51a, 52a attached to the lead ends of the grippingpieces 50, 51, 52 into the laterally movable condition so that the toolset 27 is released from locking by the gripping pieces 50, 51, 52.Thereafter, the hand 13 moves horizontally to the position that issituated somewhat before (0.2 mm before in this embodiment) the positionwhere the center of the tool set 27 coincides with the axis of the ram.

During the horizontal movement, as shown in FIG. 19, there is a verysmall gap (=0.3 mm in this embodiment) between the ring contact surface34e of the punch 28 and its associated face, between the contact surface29e of the stripper 29 and its associated face, and between the contactsurface 30e of the die 30 and its associated face. Therefore, no partscome into contact with the hand 13 during its horizontal movement,causing no touching sound (=a sound caused by interference). It shouldbe noted that in the condition just after the insertion of the tool set27, the engagement groove 32a of the clamp shank 32 and the projection61a of the engaging member 61 are in close contact with each other andthe retaining groove 29a of the stripper 29 and the projection 63a ofthe engaging member 63 are in close contact with each other.

After the horizontal movement of the hand 13 toward the specifiedposition, the hand 13 is lowered at a low speed until the contactsurface 30e of the die 30 comes into contact with its associated face,that is, a die mounting position 4c. As mentioned above, since theengagement groove 32a of the clamp shank 32 is in close contact with theprojection 61a of the engaging member 61 while the retaining groove 29aof the stripper 29 is in close contact with the projection 63a of theengaging member 63 at that time, the gripping pieces 50, 51 of the hand13 are slightly opened but the punch 28 and stripper 29 do not move.

After the die contact surface 30e has come into contact with the diemounting position 4c, the operations of the punch clamp cylinder (notshown), stripper clamp cylinders 64 and die clamp cylinder (not shown)cause the punch clamp claw 62, stripper clamp claws 65 and die clampclaw (not shown) to clamp and fix the clamp shank 32 of the punch 28,the stripper 29 and the die 30 respectively. In such a clampedcondition, a very small gap (=0.3 mm in this embodiment) is still keptbetween the ring contact surface 34e of the punch 28 and its associatedface and between the contact surface 29e of the stripper 29 and itsassociated face.

Upon the fixing of the punch 28, stripper 29 and die 30 in this way, thehand 13 moves horizontally in a direction opposite to the direction atthe time of insertion and, after reaching a specified position, itsequentially moves upward to the aforesaid stand-by position to completethe operation for mounting the tool set 27.

Upon completion of the tool set mounting as described above, a punchingoperation is performed on the workpiece interposed between the punch 28and die 30, utilizing the lower movement of the ram. A very small gap(0.3 mm in this embodiment) is created, by the punching force, betweenthe engagement groove 32a of the clamp shank 32 and the projection 61aof the engaging member 61 which have been in close contact with eachother and created, by the pressing force of the stripper 29 against theworkpiece, between the retaining groove 29a of the stripper 29 and theprojection 63a of the engaging member 63 which have also been in closecontact with each other. On the other hand, the ring contact surface 34eof the punch 28 and the contact surface 29e of the stripper 29 arebrought into close contact with their respective associated faces.

The tool set 27, which has been dismounted by the above-described toolset replacement operation, is put back to the location having itsaddress in the tool set magazine 6 in the way reverse to the operationfor taking it from the tool set holder 23.

Reference is made to FIG. 28 to describe a discharging mechanism for thematerials (products or debris remaining after punching-out) which havebeen processed in the punching operation at the work center 4.

FIG. 28 shows the discharging mechanism according to an embodiment ofthe invention, in which two parallel support rails 69 are disposed underthe main frame 1 and downstream the work center 4, running in thelongitudinal direction of the main frame 1. Supported between thesupport rails 69 are a plurality of vacuum units 70 (three units in thisembodiment). Each vacuum unit 70 comprises (i) an upright strut 71; (ii)a support frame 72 secured to the lower end of the strut 71; (iii) aholder 73 attached to the lower end of the support frame 72; and (iv)vacuum pads 74 (six pads in total) suspending from the holder 73 in tworows. First and second retaining rings 75, 76 are securely attached tothe upper end and center of the strut 71, respectively. The firstretaining ring 75 has a retaining groove, V-shaped notch and positioningpin (these are not shown) which are identical with the retaining groove34a, V-shaped notches 34b and positioning pin 34c of the retaining ring34 in the punch 28, respectively. The second retaining ring 76 has aV-shaped notch identical with the V-shaped notches 30b of the die 30.The upper support rail 69 includes notches identical with the notches35b, 35c of the tool set receiving member 35 and functioning to engageand hold the upper end of the strut 71 and the positioning pin of thefirst retaining ring 75. Projected from the lower part of the supportframe 72 secured to the main frame 1 toward the support rail 69 arefixed dogs 77 for operating the lock pins 56 of the hand 13 in the samemanner as the fixed dogs 45 of the tool set holder 23.

With the above arrangement, the gripping pieces 50, 52 of the hand 13grip, instead of the tool set 27, the first and second retaining rings75, 76 of the vacuum unit 70 supported on the support rails 69, and thedischarge of the used material W is carried out with each vacuum unit70.

For starting the discharge of the used material W, the vacuum unit 70held by the hand 13 is lowered to the absorbing position (indicated bytwo dot chain line in FIG. 28), while the material W being punched outby the punching head 4a and pressed by the stripper 29. The absorptionof the material W by the vacuum pads 74 is checked for confirmation andthe punching head 4a is then lifted. Thereafter, the hand 13 is liftedand then moved until it reaches the projecting position situated beyondone edge of the main frame 1, in order to place the material W onto amaterial discharge conveyor (not shown).

It is preferable in the embodiment that, when discharging a worn-outtool set which has been used a number of times from the machine or whenloading a new tool set into the tool set magazine 6 from outside themachine, the hand 13 be moved to the projecting position (i.e., theposition of the hand shown in FIGS. 1 and 2) situated beyond one edge ofthe main frame 1 and at this projecting position, tool set replacementbe, for instance, manually performed.

In the tool set holder 23 of the tool set magazine 6 according to theembodiment, the members of the tool set 27 are held, using the tool setreceiving sections 35A, 36A, 38A; notches 35b, 35c; and otheraccessories of the tool set receiving members 35 to 39. Instead of suchan arrangement, a retaining device for retaining the tool set 27 may beincorporated in the tool set holder. The tool to be used as the tool setis not necessarily limited to the assembly of the punch 28, stripper 29and die 30 as mentioned above, but may be a tup tool or other cuttingtools as far as they can be used in the work center 4.

According to this embodiment, the circumference of the support shaft 15is equally divided into 12 parts and the axis of the support shaft 15into 25 parts, and three hundred tool set holders in total are installedat those parts. However, the number of tool set holders is not limitedto this but may be varied as needed.

While the support shaft 15 according to the foregoing embodiment is ahollow shaft with a rectangular cross-section, the cross-section of thesupport shaft 15 may be of other polygonal shapes.

The stand-by position for the hand 13 during the punching operation inthe foregoing embodiment is a specified distance away from the workpiecein an upward direction, but this stand-by position may be separateddownwardly from the workpiece as far as the hand 13 does not interferewith the workpiece.

In the foregoing embodiment, the ring contact surface 34e of the punch28 and the contact surface 29e of the stripper 29 are brought into closecontact with their respective associated faces during the punchingoperation. The contacting method may be modified in various ways. Forexample, the parts of the punch 28 and stripper 29, which are pressedduring clamping, are tapered and tight contact is achieved when thepunch 28 and stripper 29 are clamped by the punch clamp claw 62 andstripper clamp claw 65 respectively. Another alternative is such thatthe ram is lowered by a specified amount after insertion of the tool set27 so as to eliminate the gap between the ring contact surface 34e ofthe punch 28 and its associated face and the gap between the contactsurface 29e of the stripper 29 and its associated face, and thereafterthe punch 28 and the stripper 29 are clamped.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

INDUSTRIAL APPLICABILITY

The punch press according to the invention is capable of compactly,densely storing a number of tool sets in a tool set magazine and ofquickly delivering tool sets between the tool set magazine and thepunching head. In addition, all tool sets can be used under the samecondition.

The tool set mounting method according to the invention prevents theoccurrence of a touching sound at the time of insertion of tool sets andenables high-speed tool set replacement without backlash even if thetool set delivery means is not positioned with high accuracy. Further,damage to the workpiece can be prevented when it is laid over the dieduring delivery.

We claim:
 1. A punch press comprising:a main frame for verticallysupporting a punching head, said main frame extending in a firsthorizontal direction; a work table for supporting a workpiece, said worktable extending in a second horizontal direction which is perpendicularto the first horizontal direction; a tool set magazine for storing anumber of tool sets; and tool set delivery means for delivering and formoving the tool sets between said tool set magazine and the punchinghead, wherein said tool set magazine is located vertically above thework table and a shaft having an axis about which said tool set magazinerotates extending parallel to the first horizontal direction of the mainframe.
 2. The punch press as claimed in claim 1, wherein the tool setmagazine comprises a plurality of tool set holders arranged in linesalong a horizontal support shaft, the lines of the tool set holdersbeing arranged around the support shaft.
 3. The punch press as claimedin claim 2, wherein the tool set holders are so supported as to berotatable about the support shaft.
 4. The punch press as claimed inclaim 2, wherein a punch and a die assembled in a set are held by eachof said tool set holders.
 5. The punch press as claimed in claim 1,wherein the tool set magazine is vertically separated by a specifieddistance from the position where the tool sets are mounted on ordismounted from the punching head so that the contour of the tool setmagazine does not interfere with the workpiece being processed by thepunching head.
 6. The punch press as claimed in claim 1, wherein thetool set delivery means is disposed between the tool set magazine andthe main frame so as to be movable along the support shaft of the toolset magazine.
 7. The punch press as claimed in claim 6, wherein the toolset delivery means is so disposed as to be lifted or lowered in avertical direction.
 8. The punch press as claimed in claim 7, wherein atool set loading/unloading position where the tool sets are loaded in orunloaded from the tool set magazine by the tool set delivery means islocated above or below the support shaft of the tool set magazine and isoffset to the punching head.
 9. The punch press as claimed in claim 8,wherein at the tool set loading/unloading position, the axes of thepunch and die held by the tool set holder stand upright, and thedirection in which the tool sets are loaded or unloaded at the tool setloading/unloading position lies in a plane perpendicular to the supportshaft of the tool set magazine and does not cross the support shaft. 10.The punch press as claimed in claim 7, wherein the tool set deliverymeans comprises a hand for mounting the tool sets on and dismountingthem from the punching head and for loading the tool set in andunloading them from the tool set magazine.
 11. The punch press asclaimed in claim 10, wherein the hand includes two pairs of grippingmechanisms each gripping one tool set and positioned at the respectivelead ends of two arms which together have a substantially V-shape intheir plan view.
 12. The punch press as claimed in claim 11, whereineach of the gripping mechanisms has a plurality of pairs of grippingpieces for gripping the punch and die assembled in a set and eachgripping piece has an engagement claw that comes into engagement with aV-shaped notch formed in each punch and die to retain it.
 13. The punchpress as claimed in claim 1, wherein the tool set delivery means beingmovable to a projecting position that is situated beyond one edge of themain frame and the tool sets held by the tool set delivery means can bereplaced at the projecting position.
 14. The punch press as claimed inclaim 13, wherein the projecting position is the position wherematerials which have been processed are discharged.
 15. A punch presscomprising:(a) a tool set magazine having a number of tool set holderswhich are aligned in circumferential directions and in axial directionsof a rotatably supported, horizontal support shaft and each of the toolset holders adapted to hold a set of punch and die; and (b) a tool setdelivery means for loading the tool sets in and unloading them from thetool set holder at predetermined positions in the tool set magazine,wherein each of the tool set holders has tool set receiving membersarranged at multiple levels to receive the tool sets and each of thetool set receiving members has a tool set receiving section notchedtherein in which a specified portion of each tool set is received bymoving the tool set straight ahead or laterally, and wherein the supportshaft is a hollow shaft with a polygonal cross-section, and tool setholding units, each having a plurality of the tool set holders, areattached to the external surface of the support shaft.
 16. The punchpress as claimed in claim 15, wherein the tool set magazine is locatedin close proximity to a punching head.
 17. The punch press as claimed inclaim 15, wherein each of the tool set holding units comprises a baseattached to the external surface of the support shaft; a plurality ofsupport brackets each projecting from the base at a specified angle withrespect to the circumferential direction of the support shaft; and aplurality of tool set holders each of which is attached to the lead endof each support bracket and which are juxtaposed at specified intervals.18. The punch press as claimed in claim 15, wherein each of the tool setreceiving members has engagement means for engaging each tool setinserted in its tool set receiving section.
 19. The punch press asclaimed in claim 18, wherein the engagement means is a leaf springattached to the upper or lower surface of the tool set receiving memberto engage with an engagement recess formed in each punch and die. 20.The punch press as claimed in claim 15, wherein the tool set receivingsection of the lowest tool set receiving member has, at both sidesthereof, fixed dogs for releasing a tool set holding force of the toolset delivery means.